For many years various efforts have been made to design new and better furnaces for zone refining of crystal wafers in a low or zero gravity environment by the generation of very precise melt zones with precision control of temperature gradients around the melt zone, without which portions of the crystal wafer might develop undesirable molecular and/or crystalline structural changes which could not be properly refined. The refining process in space (zero gravity) allows better control of thermal convection currents, unusual and undesirable melt zones, and more convenient ways to hold the crystal wafers without physically touching them.
It is anticipated that small, unusual type crystals, not yet even discovered, will be required for advanced detectors and semiconductors devices. Only experiments in a very low or zero gravity environment will reveal what possibilities exist and are practical.
The current problem is to provide a furnace which will be adequate to meet the rigid condition requirements of such a zone refining process.